This invention pertains generally to the reproduction of information on photosensitive surfaces, as in the production of printing plates, and more particularly to a system and method for electronic composition of a page from computer generated text and material read from a copy board or other reading surface.
In the offset printing process which has been employed for a number of years in the newspaper publishing and commercial printing industries, printed text, photographs and other graphic materials are assembled manually together to form a so-called "paste-up" of each page to be printed. A printing plate is then made from the paste-up, typically by a photographic process. This traditional prepress process is time consuming, requiring on the order of 40-60 minutes per page once the copy is ready to begin the paste-up operation.
In recent years, computers have been employed in the creation, storage and editing of text and have significantly reduced the time required for this portion of the prepress operation. Another significant reduction of time in the prepress operation has resulted from the development of a laser platemaker having reading and writing beams for simultaneously scanning the paste-up and plate. Such a device is described in application Ser. No. 758,250 referenced above.
For some time now, it has been thought that even greater savings in time could be achieved by utilizing the computer in which the text is created, stored and edited to drive the plate making device. However, prior to the present invention, no one to the knowledge of the inventors has been able to provide a commercially feasible all electronic prepress system. U.S. Pat. No. 3,949,159, issued Apr. 6, 1976, describes a system for combining computer generated text with photographs and other materials read from a drum. However, the material from the drum can only be reproduced in real time and in the same relative position in which it appears on the drum. There is no provision for storing data read from the drum, no provision for editing such data, and no provision for forming a page with data read from the drum in another position, size or format.